1. Field of the Invention
This invention relates generally to piston engines, and more particularly to a sliding-blade heat engine with a vortex combustion chamber.
2. Brief Description of the Prior Art
Piston engines are well known in the prior art. In general, the prior art piston engines employ a piston that moves up and down inside a cylinder with the piston connected to a crankshaft via a connecting rod which then translates the linear up and down motion into rotational motion. This rotational motion is then used, via a gear box or other transmission mechanism, to cause rotation of a drive mechanism to thereby impart motion to a movable vehicle.
However, conventional reciprocating piston engines have relatively complicated designs and have large energy losses associated with the conversion of the energy from the combustion of the fuel into the kinetic energy associated with work or movement.
The total mechanical losses in a piston engine can be presented as the sum of piston/ring assembly friction losses, camshaft and valving friction losses, compression and throttling work losses, and crankshaft and auxiliary devices losses. Frictional losses increase with RPM and at full speed can reach 25% of the total losses or more. Approximately 50% of the friction loss emanates from the piston/ring and cylinder interface.
In the present engine, the quantity of engaging parts is minimized and their interaction is accomplished by means of rolling which minimizes substantial friction losses compared with conventional piston engines.
Another source of mechanical loss, which is unique to the reciprocating piston engine, is an unavoidable consequence of combustion dynamic. During the process of ignition and combustion, very high pressure is spontaneously developed on the top of the piston. Due to the length of time required to complete combustion, the ignition point is usually advanced from top dead center causing an additional retarding force to develop which acts against the upward movement of the piston, thus, reducing fuel efficiency and maximum power output.
The combustion process in these dynamic conditions impedes completeness of fuel combustion that results in elevated emission of toxic components in the exhaust gases. Moreover, reciprocating piston engines require high quality fuel and the necessity of filling the cylinder volume with a dense charge of air, making exhaust heat regeneration non-suitable.
Conditions essential for reliable ignition and sustained combustion of fuel in the combustion chamber of conventional piston engines limit the value of the coefficient of air redundancy (.alpha.), which leads to high temperature of combustion products in the reaction zone and causes elevated emission of NOx.
In comparison, the vortex combustion chamber of the present invention is able to confine flame and work, thus preventing flame-out with improved completeness of combustion over the wide range of the coefficient of air redundancy (.alpha.) at non-stationary air supply. This feature decreases the toxicity of the components of the exhaust gasses considerably (including NOx), and also allows the successful use of different liquid fuels and gaseous low-grade hydrocarbon fuels, including processed products of agriculture.
Another important parameter which affects the thermodynamic performance of the conventional reciprocating piston engine is volumetric efficiency. This volumetric efficiency still remains low, typically 75% to 85% in very advanced spark ignition (SI) engines.
The presence of the crank mechanism, cylinder block, and multiple other parts in the conventional reciprocating piston engine, the pulsating character of the working process, and the limited gas distribution capacity provide principal difficulties in improving the volumetric efficiency parameter. None of these constrictions occur in the present invention.
A liquid piston engine is described in an article written by C. D. West titled "Liquid Piston Stirling Engine" Popular Science, 1983, Van Nostarand Reinhold Company, and U.S. Pat. No. 5,127,369 to Goldshtik discloses an engine employing rotating liquid as a piston.
The basic disadvantages of the liquid piston type engines are that the working fluid in such engines alters its quality due to direct contact with combustion products, and the possibility exists for developing hydraulic shocks due to sharp pressure change in the combustion chamber. Therefore, employment of these types of engines in transportation is highly problematic.
Gas turbine low-power engines are also not suitable for use as a main engine for transportation because the torque is produced by force developed by gas flowing about turbine wheel blades which gives them low acceleration characteristics. Moreover, gas turbines engines have very high speed (RPM), and rather low effective efficiency, particularly the single stage turbine engine.
Torque in the present engine, unlike the conventional turbine engine, is produced by force induced by the normal pressure of expanding gas on the surface of "sliding blades" that governs its high engine pick up, and this force is transmitted directly to a power take-off shaft without using a crankshaft, unlike conventional piston engines. The low-speed, kinematic, and characteristic properties of the working process of the present engine make it practically noiseless.
The present engine retains the following advantages of a gas turbine engine over a piston type engine:
1. High volumetric efficiency. PA1 2. Friction free sliding. PA1 3. Ability to work while overloaded. PA1 4. May employ a variety of types of combustible hydrocarbon gas or liquid fuels. PA1 5. Has reduced quantities of environmentally damaging emissions. PA1 1. Low RPM, allowing simplified engine design because a gear box is not required. PA1 2. Moderate velocity of exhaust stream, which increases internal efficiency and decreases noise level. PA1 3. Ease of fabricating sliding blades compared to blades for conventional turbines and compressors. PA1 5. Substantially increased engine pick-up.
The present engine also has the following significant advantages over gas turbine low-power engines at equal starting parameters:
Various types of vane heat engines are also known in the art, in which the work of expansion or compression is carried out in an oval-shaped working chamber formed by static surfaces in the engine body and the outer surface of a cylindrical rotor eccentrically positioned in the cavity. In most vane type heat engines, the forces arising from gas expansion or compression are absorbed by vanes which are positioned in rotor slots and reciprocate radially when the rotor rotates.
Allen, U.S. Pat. No. 5,336,059 discloses a vane-type rotary heat driven compressor; Boehling, U.S. Pat. No. 5,325,671 discloses a vane-type rotary heat engine; and Christopher et al, U.S. Pat. No. 4,037,415 discloses a vane-type implosion rotary engine.
The principal disadvantage of such engines is that the vane reciprocating movement is done by force resulting from reacting the vane tips against the solid fixed surface of the engine body. As the engine operates, the vane tips (even though equipped with special points) are subjected to intensive abrasive wear-out as a result of unlubricated friction, especially at high gas temperatures and gas contamination.
Moreover, the inlet and outlet ports in such engine designs cannot be made tangentially in the direction of rotor rotation, but rather at an angle to the rotor rotation plane in the walls of the operating chamber. This causes additional hydrodynamic losses while throttling, and decreases the efficient filling of the operating chamber of the turbine and compressor.